During the menopausal transition, women experience bone loss that can increase the risk of developing osteoporosis. Osteoporosis is a major health issue, as it affects 10 million Americans over age 50 and associated health care costs are $18 billion each year. The genetic basis of osteoporosis is not completely understood. The CYP19 gene and the VDR gene are possible contributors to the pathophysiology associated with bone loss because of their involvement in estrogen metabolism. The purpose of this retrospective, cross-sectional study is to determine if there is a significant difference in bone mineral density and rate of bone loss over a 10-year period according to VDR and CYP19 genotypes and haplotypes in a sample of women from the Baltimore Longitudinal Study on Aging (BLSA) after controlling for dietary and lifestyle factors. CYP19 and VDR genotypes and haplotypes will be evaluated using BLSA DNA samples. [unreadable] [unreadable] Factorial ANCOVA will be used to evaluate differences in BMD and rate of bone loss among subjects according to genotype and haplotype. Findings from this study will increase knowledge about CYP19 & VDR genotypes, BMD, and bone loss in women. Identification of genes that contribute to high rates of bone loss could identify women at risk for osteoporosis prior to symptoms when intervention has the best chance of impacting the health span. [unreadable] [unreadable] [unreadable]